1. Field of the Invention
This invention relates to commercial laundry equipment and, more particularly, to apparatus for extracting water from washed laundry items in preparation for their being placed in a dryer.
2. Description of the Prior Art
Laundry operations typically include some arrangement for removing a substantial proportion of the water from the items being washed, following the wash cycle. This is generally accomplished in the home laundry by rotating the washing machine tub and agitator at high speed in a so-called "spin dry" cycle. Washing machines for home laundry use typically include a spin dry cycle after both the wash and rinse cycles to remove a substantial proportion of the water prior to the next step. When the clothes are removed from the washer, they are still damp and must be dried, either by hanging on a line or placing them in a tumbler dryer.
Essentially the same operations are performed in a commercial laundry, except that a separate extractor device is employed because of the volume of laundry involved. Laundry items are washed and rinsed in washers, after which they are usually placed in bags or slings suspended from overhead tracks for transporting to the extractor, followed by placing the damp laundry in carts or by using other means such as slings for transfer to a gas dryer. Some commercial laundries are equipped for continuous operation; however, the vast majority of laundries are equipped for batch operation in which a batch of laundry items (in approximately 200 lb. dry weight increments) is processed by the washer, then transported to an extractor and finally to a dryer. The present invention is particularly directed to batch-type laundry operations.
Probably the first use of mechanical extractors involved a pair of wringer rolls, hand-cranked through a gear mechanism. These were supplanted by motor-driven wringer-roll extractors which became the common extractor means in home washing machines until after World War II. In the commercial laundry field, however, other approaches to developing effective water extracting apparatus were adopted. In the 1930's, a hay baling press was adapted to squeeze water out of wet laundry. This then developed into a hydraulic ram extractor operated at pressures in excess of 2000 psi which pressed the laundry into "cakes". These cakes were frequently so tightly compacted that it was difficult to pull them apart with hand labor.
Centrifugal extractors have been used, operating on the same principle as the spin dry cycle in home washing machines. These extractors are slow, requiring substantial time for the water from the items nearest the center to pass through the outer items before being removed from the batch. Moreover, centrifugal extractors frequently develop imbalance in the load if the items are not properly placed within the extractor, thus shutting down the machine or, on occasion, developing damage from the unbalanced load.
Another type of extractor in the prior art uses a rubber bag within a solid cylindrical housing. The batch of wet laundry is placed in the rubber bag and water pressure, pumped to 400 psi, is developed in the space between the rubber bag and the housing, squeezing the laundry inside the bag to extract the water. Apparatus operating on this principle has many maintenance problems: pumps and seals fail, rubber bags burst, etc.
I have developed an extractor for handling batches of wet laundry items which incorporates the simple, reliable, wringer roll principle in a system for automatically breaking up the batches and feeding the laundry items to the wringer roll extractor in acceptable form.